Most dental handpieces provide a supply of water and air that can be impinged on a workpiece, typically a tooth or other dental structure. The water and air are provided so as to impinge on the workpiece. This air is referred to as chip air and is to be distinguished from air that is used to power a particular type of dental handpiece, a pneumatic handpiece, that relies on a separate supply of air to power an air turbine that rotates the cutting instrument affixed to a distal end of the dental handpiece.
It is known in the art that increasing the flow of water improves the cutting ability at constant load of a tool affixed to the distal end of a handpiece, increases the cutting efficiency and decreases the cutting time of an operation. The water spray assists by keeping the workpiece, that is the tooth, cool. It also provides essential lubrication during the cutting operation. It further minimizes clogging of the tool itself, as the water flushed and carries away small particles that would otherwise become embedded in the surface of the tool, decreasing its cutting ability. These benefits were outlined in an article in CRA Newsletter Volume 25, Issue 9, September 2001, p. 2. FIG. 1 depicts the effects of varying the amount of coolant water to a dental workpiece. It is clear that increasing the amount of water decreased the cutting time.
There are tools currently available that let the dental professional physically increase the flow of water to the workpiece, if so desired by manual or foot adjustment. In many tools, this increased flow of water is provided even when the rate of cutting is reduced or diminished.
While an increased flow of water is generally desirable, there are problems associated with the increased flow of water. Specifically, water accumulation can occur in the oral cavity, even when suction for removal is provided. Furthermore, this excess water is provided even when not needed, such as when the dental professional is engaged in light cutting. The excessive water may ultimately result in the production of excessive spray that may occur when starting or backing off an operation, the excessive spray hindering visibility and impairing the ability of the dental professional in conducting a visual examination.
A dental handpiece that provides the benefits of improved water flow while overcoming the deficiencies is not available, but is much desired by dental professionals, and the present invention provides such a device.